1. Field of the Invention
This invention relates to an adapter and more particularly to an adapter to enable a wind turbine to be secured to the upper end of a wind turbine tower.
2. Description of the Related Art
A wind turbine normally comprises a rotor-driven generator mounted atop a tower which may reach heights of 70 meters or more. Upwind turbines face into the wind with those turbines utilizing a yaw drive to cause the turbine to face into the wind as the wind direction changes. Yaw drives normally include a flat, circular yaw plate or ring which is secured to the upper end of the tower with the wind turbine being rotatably mounted thereon. Prior to assignee's invention disclosed in the patent application entitled “HOLLOW STRUCTURAL MEMBER”, Ser. No. 10/797,778 filed Mar. 10, 2004, the wind turbine towers were generally tubular or cylindrical in cross section. In assignee's co-pending application, the wind turbine tower is comprised of a plurality of elongated hollow pole sections secured together in an end-to-end relationship. Each of the hollow pole sections comprised a plurality of longitudinally extending peripheral sections joined together. Each of the peripheral sections is bent along a plurality of longitudinally extending break lines to define a plurality of angled wall sections extending between inwardly extending edge portions. The edge portions of the peripheral sections are bolted together to form a hollow pole section.
The angled wall sections and the inwardly extending edge portions of assignee's wind turbine tower disclosed in the co-pending application make it difficult to secure the yaw plate of a wind turbine thereto. In other words, the upper end of assignee's wind turbine tower does not have a shape which is complementary to the shape of the wind turbine yaw plate. The mounting of a conventional wind turbine yaw plate onto the upper end of assignee's tower structure is made even more difficult due to the fact that assignee's tower structure has the inwardly extending edge portions of the peripheral sections.